Attempts are being made to develop new immunotherapy and gene therapy approaches to the treatment of patients with cancer. A variety of animal models are being used to test the effects of tumor infiltrating lymphocytes (TIL) and combinations of lymphokines in the treatment of experimental animal tumors. Current research is attempting to define the factors necessary for achieving successful immunotherapy in experimental animal models. Efforts are directed at transducing new genes into tumor infiltrating lymphocytes that can increase their therapeutic effectiveness. Genes coding for tumor necrosis factor (TNF) have been transduced and expressed in TIL and studies are underway to express genes for IL-2, IL-2 receptors, and alternate cytokine receptors in TIL. Cytokine genes are being inserted into tumors to increase their immunogenicity for use in cancer vaccines. Genes encoding melanoma tumor antigens have been cloned and sequenced and the immunodominant peptides identified. Genes encoding tumor antigens in breast and prostate cancer are being sought. A variety of clinical trials are in progress exploring the application of new vaccine approaches adoptive immunotherapies to patients with advanced cancer. Clinical trials are exploring the value of interleukin-2 alone in combination with other cytokines or chemotherapy, tumor infiltrating lymphocytes, gene modified tumor infiltrating lymphocytes, and tumor "vaccines" composed of gene modified tumor cells and recombinant viruses containing the genes encoding tumor antigens.